1. Field of the Invention
This invention generally relates to a submersible pump for pumping a fuel, such as petroleum, and to the pump manifold construction to which the outlet of the submersible pump is connected. In particular, the present invention relates to a housing unit combining a lockdown check valve assembly and a pressure relief valve assembly into one integral unit. This invention also relates to a method for assembling/disassembling the unit with respect to the outlet of the submersible pump.
2. Background of the Related Art
Conventional pumping systems are used for pumping a product, such as fuel, from an underground tank to a dispensing station aboveground. There are several problems associated with these systems, one problem relating to the inconvenience associated with having the pumping system located underground. For instance, annual maintenance checks must be conducted under local and federal laws, for leaks in the underground piping. These maintenance checks are required to prevent contamination of the soil with petroleum products. However, in conventional systems it is difficult to conduct these checks because the dispensing line must be cut off from the pumping line to get a seal within the dispensing line itself.
Under federal law, the dispensing lines must be checked for leaks on a regular basis, so as to prevent contamination to the soil near the underground pipes. In addition, prevention of leaks is desired from an economical point of view, since leaks are inefficient and costly. In order to obtain an accurate test of a dispensing line, the line must be sealed off, including the end located at the outlet end of the pumping assembly.
In addition, conventional pressure relief valves, such as the one disclosed in U.S. Pat. No. 2,149,602, regulate the pressure of delivery by the pump so that any excess over that pressure will be relieved by the relief valve by adjusting a screw plug. However, there is no feature for adjusting the pressure to be a predetermined amount. In addition, the pressure relief valve is remotely located from the check valve, which is inconvenient when mandatory leak checks must be made of the dispensing lines since this valve should be closed off at that time.